Anyone use this FD in their setup's at all?

applied with a close ratio gear set, what kind of power out put do you have to make this fd with close gears usable?

 

I have been wondering the same about that ratio

 

With any of the available close gear sets, power won't be an issue.

The Civic VX utilized a 3.25 FD with less power than any B series ever had.

You will want to use the shortest ratios possible while still hitting your top speed needs in each gear for the track you're running on.

If this is for a drag application, I do not suggest it, as the car will be very slow off the line compared to a 4.7/4.9 setup.

 

It would work excellent for roll racing, keeps a higher top speed while allowing a 5th gear cuff.

Calling Gringo.....

 

Without changing to short ratio gears it will also slow the car down a lot. It does gain an additional 41mph in 4th with no gear change.

 

So a close gear set with a 3.471. just to be clear.

this is not a FD for drag i understand. but the over power band. down low and ossibly mid end are no going to be that great in comparison to a 4.92 for example with a close gear set BUT i will maintain the top end power + the top speed.

so even say with a F.I. 300+ hp engine ( i know there are other factors but just for understanding) the 3.471 is going to be more beneficial for Speed?

if that is the case is acceleration lost quite a bit even if the rpm's are even in the ideal range of the gears? ( so slowing down for a corner, down shift, rpms still in the high power band, turn corner, WOT, shift.) How would acceleration like that compare to something like a stock fd or a 4.92.

so like is the accel. substantial being in the power band because of high top speeds being a able to be achieved? or am i going to experience a more less aggressive transition but climbing to a higher greater top speed?

assuming a FD like this is purely road course, longer and less slow turn type course.
so no auto-x,drag,hill climbs?

having a hard time comprehending this for some reason

 

Gearing does not affect power and the FD doesn't affect RPM drop.

There are several close gear sets available so there are a lot of combinations that can be done. For most setups (most track cars are NA) you would want to use the shortest ratios (1.207 5th). Doing that you maintain similar top speeds to the 4.05 FD, longest ratio gesrs (of the available MFactory close gear set ratios) setup.

 

Here is a comparison with the shortest ratios vs. a stock gear 4.923 setup. The 3.7 trans could use a midrange 5th for a more even RPM drop and higher top speed.

MFactory® Competition Products - Gear Calculator

 

One thing that is actually confusing me even more now is torque multiplication.

correct me if i am wrong but i feel like.... ok so two exact same engines/cars, but with different transmissions one is always going to accell faster or am i wrong? (see below)

i messed around with the calc. did a bunch of math... and am lost or am i thinking to hard about this?

so lets say a 260/184tq hp engine. with a versus of these 2 tranys

1 trany has close gears and a 3.47, while the other is stock gears with a 4.92.

from what i can tell the only benefit from a 3.47/close gear are that the rpms are always way up high in the power band and a greater top speed and/or thrust of the vehicle.

while the 4.92 has a lower top speed. less thrust but in and out of corners in mid to high rpm will always out accell (to a point) the 3.47 with or with out close gears. is this correct?


for example. with my track, what i am struggling with is this. my s80 tran. with a 4.92
so:
3.23
2.10
1.24
1.10
0.84
FD:4.92

it is good until i hit the longer faster parts of the track, coming out of corners and handling are awesome, launch out of the corner is awesome, but hitting the top speeds is when i start loosing time and even getting passed.
sure when i am back in the some what slower sections i can catch up to other drivers but i do not really make up time as i lose it again on the fast top end sections

what i wanted to build was this

2.23
2.10
1.63
1.31
1.05
FD:3.47

it seems ideal, but i am worried about the TQ multiplication now in the slower some what twisty sections in regards to how it performs with the stock + 4.92.

 

You're overthinking it. Don't worry about torque mulitplication.

Two factors for transmission when it comes to acceleration. The ramp rate (how fast the gearing makes the car accelerate) and the RPM drop (closer ratio gears will yield more power being put down on upshifts which increases acceleration but cannot be seen in the ramp rate).

For the close ratios you want you would be better off with the 4.0 FD. That is the most common setup I build for B series track cars.

 

So when you say that, is it more of a placebo effect? feeling the acceleration versus he acceleration actually having an effect.

sp up shifts having more acceleration in the context of speed rather than the conttext of "g-force" or that throw in the seat feeling.

for my understanding if i may ask, why do you recommend the 4.0 instead of the 3.471? 4.0 being the most common with YOUR experience ( as i have not raced a civic with a fd under 4.4) with what i am wanting, what does the 4.0 offer that the 3.471 does not?

i mean, i understand the 4.0 is going to allow a greater "off the line" versus the 3.471 but wont the "ramp" rate and overall thrust/momentum of the car be greater with the 3.471?

 

Acceleration is acceleration.

The ramp rate is slower with the 3.4 so acceleration will be slower, given the same ratios. I recommend the 4.0 unless you want to use the shorter ratios available.

 

hmm given me a bit to think about now. thnx for the help aqua